Optically Pumped Microplasma Lasers

ABSTRACT

A laser and methods for providing a continuous wave output beam. The laser and method includes positioning a micro-plasma chip capable of creating micro-plasmas within a resonant cavity. A gas is input into the resonant cavity and flows around the micro-plasma chip. Micro-plasmas ignite and excite the gas to create metastables. The metastables are further excited by an optical pump having an energy sufficient to cause the metastables to lase.

GOVERNMENT RIGHTS

The invention was made with government support under U.S. Air ForceContract No. FA8650-11-M-2203, “Radio Frequency (RF) Microplasma forOzone Generation”; U.S. Air Force Contract No. FA8650-12-C-2312, “RFMicroplasmas for Energetic Species Generation”; and U.S. Air ForceContract No. FA8650-11-M-2203, “Diode-Pumped Rare Gas Laser.” Thegovernment may have certain rights in the invention.

FIELD OF THE INVENTION

This invention relates generally to devices, systems, and methods forgas phase lasers. More specifically, the invention relates to a gasphase laser that is optically pumped and includes a micro-plasma chip.

BACKGROUND OF THE INVENTION

Optically pumped lasers can provide output having wavelengths betweenultra-violet and far infrared regions of the electromagnetic spectrum.Current optically pumped lasers include atomic and molecular lasers.Pump sources for optically pumped lasers can include flash lamps,semi-conductor lasers, light emitting diodes, solid state lasers, gaslasers, dye lasers, and/or any optical pump source having appropriatewavelengths (e.g., neon: 640.4 nm, argon: 811.7 nm, krypton: 811.5, andxenon: 882.2 nm). Diode lasers can provide higher output powers andhigher efficiency in operation compared to flash lamps. For example,diode pumped alkali lasers (DPAL) can be provide high output powers(e.g., over 1 kW output power from a cesium DPAL).

Optically pumped lasers can operate by pumping a ground state of an atomor a molecule to an excited state that either lases or undergoescollisional transfer to a nearby excited state that subsequently lases.FIG. 1 is an exemplary diagram 100 representing multiple states of a gas(atoms or molecules) that is optically pumped. The gas begins in a firstground state (1). The gas is optically pumped (e.g., by a diode) andtransitions to a second excited state (2). In the second excited state(2), the gas collides further exciting the gas to a third excited state(3). In the third exited state (3), more collisions occur and the gascontinues to have increasing energy, which eventually causes the gas totransition to a fourth excited state (4) of lasing. While opticallypumped lasers can lase, they can be limited to gas species types thathave ground states that are capable of transitioning by opticalexcitation.

Additional optically pumped lasers that can lase with the use of raregas atoms (e.g., argon, krypton, and/or xenon) are available. Theselasers typically optically pump from one excited state to anotherexcited state that then lases. These lasers have only operated in apulsed mode and usually do not operate at atmospheric pressure. Pulsedmode lasers are only “on” for a brief period of time, for example, a fewnanoseconds to a fraction of a nanosecond. Therefore, pulsed mode lasersare typically not efficient at delivering a steady output beam. For someapplications, e.g., Laser Identification and Ranging (LIDAR), pulse modeis desired, for many other applications, e.g., medical diagnostics,laser machining, and/or other laser material interactions, a continuouswave output beam is desired. Additionally, rare gas atoms are chemicallystable and typically do not react with any surface in the laserincluding the optics. This can enable a lasant to be used indefinitelyin a sealed system or readily flowed in a sealed system.

Therefore, it is desirable to lase rare gas atoms with an optical pumpin a continuous mode. It is also desirable to lase rare gas atoms atatmospheric pressure.

SUMMARY OF THE INVENTION

Generally, a laser includes a micro-plasma chip positioned within aresonant cavity, an atomic (or molecular) gas flows through the resonantcavity and surrounds the micro-plasma chip. The micro-plasma chipignites and maintains a plurality of micro-plasmas, the micro-plasmasexcite the gas to create metastables (atoms or molecules). An opticalpump directs light onto the micro-plasmas and metastables to furtherexcite the metastables to an excitation for which lasing occurs.

Advantages of the claimed invention include high output power (e.g., >1kW) and higher laser efficiency due to, for example, kinetics andproperties of the states of rare gases. Advantages also include highoptical gain (e.g., 2.2/cm). High optical gain can allow the opticallypumped micro-plasmas to be used as an optical amplifier. Plasmacontaining metastable atoms can be an amplifying medium when opticallypumped. The plasma medium can increase the intensity of a beam of lightthat has substantially the same optical frequency as the rare gas atomictransitions in the plasma.

Another advantage of the invention is that lasing can occur using raregases (e.g., neon, krypton, argon and/or xenon), allowing for diversityof output wavelengths. Another advantage is a continuous wave outputover a range of wavelengths (e.g., ˜650 nm to 1900 nm) over an extendedduration (e.g., ˜30 minutes). The range of wavelengths can allow for a)atmospheric propagation (certain colors are not absorbed and canpropagate long distances, e.g., greater than 1 km, and b) propagation intissue which can be helpful in, for example, medical applications. Therange is also advantageous in laser machining.

Another advantage is ease of circulation of the gas. During high poweroperation, waste heat is typically unavoidable because the laserstypically operate at wavelengths that are longer than that of the pumplaser wavelength. This is known as the “quantum defect”. The quantumdefect can be high because in high power solid state lasers (e.g.,Nd:YAG) it can be difficult to rapidly remove the waste heat. The wasteheat can cause optical aberrations in the laser medium. Opticalaberrations in the laser medium can cause a degraded beam quality of thelaser output beam. A flowing gas lasers that has recirculation of thegas through the laser improves waste heat removal, thus allowing for abetter beam quality of the laser output beam.

In one aspect, the invention includes a laser for providing a continuouswave output beam. The laser is configured to receive light from a lightsource.

The laser includes a micro-plasma chip and a resonant optical cavity forhousing the micro-plasma chip at a location that allows a gas flowingwithin the resonant cavity to surround the micro-plasma chip, such thatthe micro-plasma chip generates a plurality of micro-plasmas thatinclude excited metastable atoms. The laser also includes an opticalpump positioned relative to the micro-plasma chip to direct light fromthe light source onto the micro-plasmas to optically pump the metastableatoms to cause lasing of the gas sufficient to generate the continuouswave output beam.

In some embodiments, the gas is Argon, Helium, Neon, Krypton, Xenon,Nitrogen, Oxygen or any combination thereof. In some embodiments, themicro-plasma chip operates at a microwave frequency. In someembodiments, the cavity is less than 2 cm in length.

In some embodiments, the laser includes a plurality of resonant opticalcavities fluidly connected to each other, each of the plurality ofcavities having a micro-plasma chip disposed therein and an opticalresonator disposed relative to the micro-plasma chip.

In some embodiments, the micro-plasma chip includes multiple resonatorsthat provide energy to the micro-plasmas. In some embodiments, one ofthe multiple resonators receives power from a power source, such thatsaid resonator provides power to the remaining resonators of themultiple resonators that do not receive power directly from the powersource. In some embodiments, the laser is configured to operate atatmospheric pressure.

In another aspect, the invention involves a method for providing acontinuous wave output beam from a laser. The laser configured toreceive light from a light source. The method involves providing a flowof gas into a resonant optical cavity and applying power to amicro-plasma chip that is positioned within the resonant cavity at alocation that allows the gas to surround the micro-plasma chip causingthe micro-plasma chip to generate a plurality of micro-plasmas thatinclude excited metastable atoms. The method also involves directinglight from the light source onto the plurality of micro-plasmas tooptically pump the metastable atoms to cause lasing of the gassufficient to generate the continuous wave output beam.

In some embodiments, the method involves operating the micro-plasma chipat a microwave frequency. In some embodiments, the method involvesproviding a flow of Argon, Helium, Neon, Krypton, Xenon, Oxygen orNitrogen gas, or any combination thereof, into the resonant opticalcavity.

In some embodiments, the method involves providing a plurality ofresonant optical cavities fluidly connecting each other, each of theplurality of cavities having a micro-plasma chip disposed therein and anoptical resonator disposed relative to the micro-plasma chip.

In some embodiments, the method involves providing power to oneresonator of multiple resonators included the micro-plasma chip, suchthat said resonator provides power to the other resonators of themultiple resonators that do not receive power directly from the powersource.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the invention described above, together with furtheradvantages, may be better understood by referring to the followingdescription taken in conjunction with the accompanying drawings. Thedrawings are not necessarily to scale; emphasis instead is generallyplaced upon illustrating the principles of the invention.

FIG. 1 is an exemplary diagram representing states of gas (atoms ormolecules) that are optically pumped, according to the prior art.

FIG. 2 is an exemplary diagram representing states of gas (atoms ormolecules) that are pumped by a micro-plasma discharge to a firstexcited state before being optically pumped, according to anillustrative embodiment of the technology.

FIG. 3 is a block diagram of a micro-plasma laser system, according toan illustrative embodiment of the technology.

FIG. 4 is a three-dimensional diagram of a micro-plasma laser, accordingto an illustrative embodiment of the technology.

FIG. 5A is a three-dimensional diagram of a micro-plasma chip, accordingto an illustrative embodiment of the technology.

FIG. 5B is a two-dimensional diagram of a portion of the micro-plasmachip of FIG. 5A.

FIG. 6A is a three dimensional diagram showing positioning of elementsof a laser, according to an illustrative embodiment of the technology.

FIG. 6B is a graph showing laser output power vs. time for an embodimentof the laser configured according to FIG. 6A.

FIG. 7 is a graph showing spectra for excited argon species produced bya micro-plasma, according to an illustrative embodiment of thetechnology.

FIG. 8 shows a series of images of a laser induced fluorescence for alaser having a Ti:S laser pump at 811 nm with various optical pumppowers and an input gas of argon, according illustrative embodiments ofthe technology.

FIG. 9A is an image of an output laser beam, according to an embodimentof the technology.

FIG. 9B is a graph 950 showing the output laser beam in FIG. 9A in apixel view.

DETAILED DESCRIPTION OF THE INVENTION

Generally, a laser includes a micro-plasma chip positioned within aresonant cavity, an atomic (or molecular) gas flows through the resonantcavity and surrounds the micro-plasma chip. The micro-plasma chipignites and maintains a plurality of micro-plasmas, the micro-plasmasexcite the gas to create metastables (atoms or molecules). An opticalpump directs light onto the micro-plasmas and metastables to furtherexcite the metastables to an excitation for which lasing occurs.

The micro-plasma chip is located within the resonant optical cavity at aposition that allows the gas flow to surround the micro-plasma chip andthe light to impinge on the micro-plasmas.

FIG. 2 is an exemplary diagram 201 representing states of gas (atoms ormolecules) that are pumped by a micro-plasma discharge to a firstexcited state before being optically pumped, according to anillustrative embodiment of the technology. The gas starts in a groundstate (G). A micro-plasma excites the gas to a first excited state (1)(e.g., transitions the gas to metastables). A light source is impingedon the micro-plasma that optically pumps the metastables from the firstexcited state (1) to a second excited state (2). In the second excitedstate (2), the metastables collide further exciting the metastables to athird excited state (3). In the third excited state (3), more collisionsas well as further pumping from the micro-plasmas occurs and the gascontinues to have increasing energy, which eventually causes themetastables to transition to a fourth excited state (4) of lasing.

FIG. 3 is a block diagram of a micro-plasma laser system 300, accordingto an illustrative embodiment of the technology. The micro-plasma lasersystem includes a resonant optical cavity 338, a micro-plasma chip 337,an optical pump 301, a power meter/beam dump 360, a power meter 365, awave meter 310, and a plurality of optical elements 305, 315, 345, 320,330 a, 330 b, and 348.

The optical pump 301 outputs a pump laser beam that impinges uponoptical element 305. In some embodiments, the optical pump 301 is atitanium: sapphire laser, flash lamp, semi-conductor laser, lightemitting diode, solid state laser, gas laser, dye laser, and/or anyoptical pump source having appropriate wavelengths. In some embodiments,the optical pump 301 is any optical pump known in the art to output abeam sufficient to pump metastables produced by the micro-plasmas totransition to lasing (e.g., as in the case of argon gas, a population of3p⁵4s metastables at atmospheric pressure). The micro-plasma chip 337 ispositioned within the resonant optical cavity 338. In some embodiments,optical element 305 is a mirror.

The optical element 305 directs a first portion of the pump laser beamto impinge upon the wave meter 310 and a second portion of the pumplaser beam to impinge upon the optical element 315. The wave meter 310can determine the wavelength of the pump laser beam. Optical element 315adjusts a polarization of the pump laser beam such that the pump laserbeam exits the optical element 315 with a horizontal orientation. Insome embodiments, the optical element 315 is a half-wave plate. Theoptical element 315 rotates the plane polarization of the pump laserbeam by 180 degrees to allow injection of the pump laser beam into theresonant optical cavity 338 without having to pass the pump laser beamthrough a resonant minor.

The horizontally oriented pump laser beam impinges upon the opticalelement 345. Optical element 345 reorients the horizontally orientedpump laser beam to a vertical orientation and directs the verticallyoriented pump laser beam to impinge upon the optical element 320. Theoptical element 320 directs the pump laser beam into the resonantoptical cavity 338. In some embodiments, the optical element 320 is abeam splitter prism.

The optical element 320 directs the pump laser beam to impinge upon theoptical element 330. The optical element 330 directs the pump laser beamtowards the resonant optical cavity 338. In some embodiments, theoptical element 330 is a focusing lens.

The pump laser beam travels through the resonant optical cavity 338 andimpinges upon an area of the micro-plasma chip 337 where micro-plasmascan ignite. The pump laser beam pumps metastables created by themicro-plasmas to an energetic state for which lasing occurs. Once lasingoccurs, the output laser beam exits the resonant cavity 338. The outputbeam can be a continuous wave laser beam.

In some embodiments, an optical pump is positioned to direct a pumpingbeam substantially orthogonal to the direction of lasing, e.g., sidepumping is performed.

The micro-plasma laser system 300 can operate at both above and belowatmospheric pressure. In various embodiments, the micro-plasma lasersystem 300 operates at pressures ranging from 15 torr to 760 torr. Themicro-plasma laser system 300 can produce a continuous wave output beam.In some embodiments, the input gas is neon, krypton, argon, xenon or anycombination thereof. In some embodiments, the micro-plasma laser system300 is used produce an energetic excited-state species (e.g., metastablemolecular nitrogen, N₂(A³Σ_(u)) or metastable oxygen (O₂(a¹Δ).

During operation, the resonant optical cavity 338 receives gas as input(gas input not shown). The gas has a predetermined concentration and apredetermined flow rate. The gas concentration and flow rate can bebased on the input pressure and the output pressure of the resonantoptical cavity 338. In some embodiments, the gas concentration is argondiluted in helium (e.g., argon diluted in ˜2% helium). In someembodiments, the gas concentration is 1% to greater than 10%. In variousembodiments, the gas flow rate into the resonant optical cavity 338ranges from 0.5 mmoles/s to 0.9 mmoles/s.

During operation, the micro-plasma chip 337 receives power from a powersource (not shown). The power source provides power to the micro-plasmachip 337 such that micro-plasma can form within the chip. In someembodiments, the power source provides a microwave power. In someembodiments, the microwave power is ˜900 MHz. In some embodiments, themicrowave power is driven by a power amplifier. The power amplifier canbe a 30 W, 0.7-2.52 GHz power amplifier. In some embodiments, the poweris connected to the micro-discharge chip 337 via coaxial cabling and/oran SMA vacuum feed through on the resonant optical cavity 338.

In some embodiments, the micro-plasma laser system 300 operates with aresonant optical cavity 338 having a pressure of one atmosphere, anoptical resonant cavity input gas having a composition of 2% argon, 98%helium and a gas flow rate of 0.0037 moles/s, a micro-plasma dischargegas temperature of ˜300° C., a microwave power to micro-plasma dischargeof 9 W, and an excitation laser intensity of 1300 W/cm².

In various embodiments, the micro-plasma laser system 300 operates witha pressure ranging from 0.1 to 1.0 atmosphere, a gas composition rangingfrom 0.5% to 40% argon, a balance helium, a gas flow rate ranging from0.0037 to 0.0074 moles/s, a micro-discharge temperature of ˜300° C., amicrowave power to micro-discharge of 9 W and/or an excitation laserintensity ranging from 500 to 6500 W/cm². In some embodiments, themicro-plasma laser system 300 operates with a pressure that can begreater than an atmosphere.

In various embodiments, the micro-plasma laser system 300 operates witha pressure that is greater than or equal to 0.01 atmosphere, a gascomposition ranging from 0.1% to 100% lasant parent gas, a balancehelium or argon diluent, a gas flow rate greater than or equal to 0.001mole/s, a micro-discharge temperature greater than or equal to 20° C., amicrowave power to discharge greater than or equal to 5 W and/or anexcitation laser intensity greater than or equal to 500 W/cm².

FIG. 4 is a three-dimensional diagram of a micro-plasma laser 400,according to an illustrative embodiment of the technology. Themicro-plasma laser 400 includes a resonant optical cavity 401, amicro-plasma chip 402, a gas input 403, multiple gas outputs 404 a, 404b, 404 c, 404 d, 404 e, generally, 404, laser beam output 405, anoptical pump input 406, an optical pump output 407, and an opticalwindow 408.

The resonant optical cavity 401 has the micro-plasma chip 402 positionedtherein. A gas flows into the resonant optical cavity 401 via gas input403. During operation, the micro-plasma chip 402 is powered with a powersource (not shown). The gas surrounds the micro-plasma chip 402 andmicro-plasmas ignite. The micro-plasmas create metastables from thesurrounding gas.

An optical pump (not shown) directs light through the optical pump input406. The micro-plasma chip 402 is positioned such that the directedlight impinges upon the micro-plasma chip 402 at a location along aportion of the chip where the micro-plasmas exist and at a locationwhere there is a high concentration of metastables. The metastables areexcited by the light such that lasing occurs. The output laser beamexits the resonant optical cavity 402 via the laser beam output 405. Theportion of the directed light that does not energize the metastablesexits the resonant optical cavity 402 at the optical pump output 407.Unused gas exits the resonant optical cavity 402 at the gas outputs 404.In some embodiments, the resonant optical cavity 402 is a glass-filledTeflon flow plenum.

FIG. 5A is a three-dimensional diagram of a micro-plasma chip 500,according to an illustrative embodiment of the technology. FIG. 5B is atwo-dimensional diagram of a portion of the micro-plasma chip 500,according to an illustrative embodiment of the technology.

The micro-plasma chip 500 includes a ground strip 510, a power input520, a plurality of resonators, 525 a, 525 b, 525 c, 525 d, . . . , 525n, generally 525 and insulating material 530 a, 530 b, 530 c, . . . 530n. During operation, a power is applied to the micro-plasma chip via thepower input 520. A gas flow is provided such that the gas surrounds thechip. The plurality of resonator 525 ignite micro-plasmas in the regionsof plasma 505 a, 505 b, 505 c, 505 d, . . . , 505 n, generally 505. Insome embodiments, the number of resonators is 15. It is apparent tothose skilled in the art that any number of resonators that causes amicro-plasma to transition gas to a metastable state sufficient to bepumped for lasing can be used.

In one exemplary embodiment, the micro-plasma chip 500 can provide aplasma power of ˜3 watts. The micro-plasma chip can have a plasmaignition voltage of less than 20 volts, a plasma sustaining voltage ofless than 20 volts, an operating frequency of 915 megahertz, anelectrode sputtering that is negligible, a mode of operation that iscontinuous, and any combination thereof. In embodiments where argon isthe input gas, the average electron density in is ˜10 ¹⁴ cm⁻³.

The micro-plasma chip 500 can be any micro-plasma chip as known in theart. For example, the micro-plasma chip 500 can be a micro-plasma chipas shown in WO Publication No. 2012/129277 by Hopwood et al, the entirecontents of which are incorporated herein by reference.

FIG. 6A is a three dimensional diagram 600 showing positioning ofelements of a laser, according to an illustrative embodiment of thetechnology. A pump laser beam 615 is impinged upon a beam splitter 620from, for example, a Ti:S laser (not shown). The beam splitter 620splits the pump laser beam 615 such that a first portion of the beamdirectly impinges upon a region of micro-plasma 625 (e.g., themicro-plasma generated by the micro-plasma chip 337 as discussed abovein FIG. 4) and a second portion of the beam 610 impinges upon aresonator mirror 605 a. The resonator mirror 605 a reflects light intothe region of micro-plasma 620. The region of micro-plasma 620 includesa volume outside of a micro-chip that contains metastable atoms that arecreated by the micro-chip. The metastable atoms can be optically excitedand lased.

The pump laser beam 615 is directed to the region of micro-plasma 620and impinges upon the resonator minor 605 b. The resonator mirror 605 breflects the pump laser beam 615 through the region of micro-plasma 620.During operation, lasing occurs and an output laser beam 601 exits thelaser. In one exemplary embodiment, the region of plasma 620 is ˜1.9centimeters long, 300 micrometers high and 500 to 900 micrometers wide.

In some embodiments, the resonant mirrors have an ˜15% transmission foran optical pump of 912 nm. In some embodiments, the optical conversionefficiency is 55%.

FIG. 6B is a graph 650 showing laser output power vs. time for anembodiment of the laser configured according to FIG. 6A.

FIG. 7 is a graph 700 showing spectra for excited argon species producedby a micro-plasma, according to an illustrative embodiment of thetechnology. The spectra in graph 600 are for a micro-plasma chip (e.g.,the micro-plasma generated by the micro-plasma chip 337 as discussedabove in FIG. 4) having 15 resonators with a gas flow of argon and anoptical pump of a Ti:S continuous wave laser. The spectra show anintense emission (e.g., S5->P9) for several argon states in the 12-14 eVrange.

FIG. 8 shows a series of images, 800 a, 800 b, 800 c, 800 d, 800 e, and800 f, of a laser induced fluorescence for a laser having a Ti:S laserpump at 811 nm with various optical pump powers and an input gas ofargon, according illustrative embodiments of the laser.

The intensity corresponds to active regions of the micro-plasma wherethe metastable concentrations are the highest. For example, for lowlaser power of ˜50 mW, the Ti:S laser is completely absorbed in thefirst half of a 1.9 cm path length of the micro-plasma. As the laserpower increases (100-200 mW) the pump laser transmits increasinglylonger path lengths of the argon metastables. When the Ti:S laser powerincreases to greater than 300 mW, the medium is transparent because thepump transition in the argon is saturated.

FIG. 9A is an image 900 of an output laser beam, according to anembodiment of the technology.

FIG. 9B is a graph 950 showing the output laser beam in FIG. 9A in apixel view.

While the invention has been particularly shown and described withreference to specific embodiments, it should be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

What is claimed is:
 1. A laser for providing a continuous wave outputbeam, the laser configured to receive light from a light source, thelaser comprising: a micro-plasma chip; a resonant optical cavity forhousing the micro-plasma chip at a location that allows a gas flowingwithin the resonant cavity to surround the micro-plasma chip, such thatthe micro-plasma chip generates a plurality of micro-plasmas thatinclude excited metastable atoms; and an optical pump positionedrelative to the micro-plasma chip to direct light from the light sourceonto the micro-plasmas to optically pump the metastable atoms to causelasing of the gas sufficient to generate the continuous wave outputbeam.
 2. The laser device of claim 1 wherein the gas is Argon, Helium,Neon, Krypton, Xenon, Nitrogen, Oxygen, or any combination thereof. 3.The laser device of claim 1 wherein the micro-plasma chip operates at amicrowave frequency.
 4. The laser device of claim 1 wherein the cavityis less than 2 cm in length.
 5. The laser device of claim where thecavity is between 1 cm and 100 cm in length.
 6. The laser device ofclaim 1 further comprising a plurality of resonant optical cavitiesfluidly connected to each other, each of the plurality of cavitieshaving a micro-plasma chip disposed therein and an optical resonatordisposed relative to the micro-plasma chip.
 7. The laser device of claim1 wherein the micro-plasma chip includes multiple resonators thatprovide energy to the micro-plasmas.
 8. The laser device of claim 6wherein one of the multiple resonators receives power from a powersource, such that said resonator provides power to the remainingresonators of the multiple resonators that do not receive power directlyfrom the power source.
 9. The laser device of claim 1 wherein the laseris configured to operate at atmospheric pressure.
 10. A method forproviding a continuous wave output beam from a laser, the laserconfigured to receive light from a light source, the method comprising:providing a flow of gas into a resonant optical cavity; applying powerto a micro-plasma chip that is positioned within the resonant cavity ata location that allows the gas to surround the micro-plasma chip causingthe micro-plasma chip to generate a plurality of micro-plasmas thatinclude excited metastable atoms; and directing light from the lightsource onto the plurality of micro-plasmas to optically pump themetastable atoms to cause lasing of the gas sufficient to generate thecontinuous wave output beam.
 11. The method of claim 9 furthercomprising operating the micro-plasma chip at a microwave frequency. 12.The method of claim 9 further comprising providing a flow of Argon,Helium, Neon, Krypton, Xenon, or Nitrogen gas, or any combinationthereof, into the resonant optical cavity.
 13. The method of claim 9further comprising providing a plurality of resonant optical cavitiesfluidly connecting each other, each of the plurality of cavities havinga micro-plasma chip disposed therein and an optical resonator disposedrelative to the micro-plasma chip.
 14. The method of claim 9 furthercomprising providing power to one resonator of multiple resonatorsincluded the micro-plasma chip, such that said resonator provides powerto the other resonators of the multiple resonators that do not receivepower directly from the power source.